<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .box1 {
        width: 200px;
        height: 200px;
        background-color: skyblue;
        float: left;
      }
      .box2 {
        width: 250px;
        height: 250px;
        background-color: springgreen;
        float: left;
        /* clear: left; */
        /* clear: right; */
        clear: both;
      }
      .box3 {
        width: 300px;
        height: 300px;
        background-color: orange;
        float: left;
      }

      /* 
        clear清除浮动元素对当前元素的影响
          可选值  left
                  right
                  both清除两侧中影响最大的那一侧
      */
    </style>
  </head>
  <body>
    <div class="box1">1</div>
    <div class="box2">2</div>
    <div class="box3">3</div>
  </body>
</html>
